The objective of this study is to clarify the mechanisms responsible for the genesis of myopia and to develop procedures to prevent this condition. We have shown that surgical lid fusion in neonatal macaque monkeys causes an axial length myopia that is very similar to the human refractive error. In the rhesus macaque, elongation of the eye is primarily caused by disruption of the control of eye growth that is exerted by the retina. In contrast, eye elongation in the stump-tailed macaque is mainly due to the central nervous system through excessive accommodation. The application is concerned with (a) identification of the molecule/s released by the retina that modulate eye growth in the rhesus macaque and testing their effects both in vivo and in vitro; (b) inducing myopia in stump-tailed macaques by forcing the animal to accommodate through behavioral control; (c) assessing the relative contribution of the retina and central nervous system to the pathogenesis of lid-suture myopia in these two primate species.